In the manufacture of electronic circuitry of the type which utilizes circuit boards having discrete devices such as capacitors mounted thereon, it has been found to be highly advantageous to eliminate manual insertion techniques, as such techniques are expensive and subject to operator error. Alternate techniques directed to the automatic placement of parts are more desirable in that they decrease costs and reduce the number of errors that are normally committed in the fabrication of the circuit board. Electrical components which have leads also have lead inductance. Such inductance causes limitations in signal handling capabilities of a circuit using such components. It would therefore be highly desirable to have an electrical component that requires no leads. Once the desirability of automatic handling of the insertion and fastening of discrete components to the circuit board is decided upon, then the problems associated with handling the particular discrete component becomes acute. Some of the problems are of course the physical design of the component such that the fabricating machine can index the component in the correct polarity and/or angular relationship with respect to the conductors on the circuit board and also in the physical transportation of the component from the parts bin to the circuit board under fabrication. In addition, there also exists the problem associated with the handling of different size discrete components. A number of configurations have been proposed for facilitating the automatic placement of electronic components on circuit boards. One such configuration is disclosed in U.S. Pat. No. 2,990,498 entitled "Capacitor" by S. W. Evans. The component disclosed is a capacitor which is particularly adaptable to being inserted into a circuit board. More specifically, there is disclosed a capacitor which is trapezoidal in shape and which is formed from a dielectric material having electrical plates positioned on either side of the dielectric material. The capacitor is designed to be inserted edgewise into a rectangular hole in the circuit board. With such a mounting the electrical plates are forced into electrical contact with corresponding conductors on the circuit board and are soldered to the circuit board to provide a rigid support for the capacitor component. It is to be noted, that the opening into which the component is to be inserted is by necessity rectangular in shape. Rectangular holes are more difficult to cut than are circular holes.
Another patent of interest is U.S. Pat. No. 3,142,783, entitled "Electrical Circuit System" by W. B. Warren wherein there is disclosed a circuit board having a hole drilled there through for receiving an electrical component which component is cylindrical in shape. Each end of the cylindrical shaped component and/or housing for a component has an electrical conductor affixed thereto for making contact with electrical conductors on the circuit board. One end of the hole in the circuit board is provided with tabs that project into the opening area so as to limit the travel of the component when it is inserted into the circuit board. For the particular configuration of the electrical component shown, the conductors are positioned on each end of the cylindrically-shaped element. This limits the number of electrical contacts that the component may be physically connected to in terms of a multi-layer device, that is, only the board conductors that are in the plane of the two end conductors can be physically in contact with the two end conductors. In addition, the circuit board must be provided with an additional layer which layer contains the indexing and/or stop tabs for the electrical component.
Another device of interest is disclosed in U.S. Pat. No. 3,218,584 entitled "Strip Line Connection" by D. R. Ayer. The device disclosed in the subject patent is one which can make contact to a multi-layer printed circuit board in that multi-layers of the component are provided which layers and associated contacts are designed to come into contact with associated circuit board layers when the component is fully inserted in the board. It is to be noted that the device is rectangular and/or square in shape and the receiving holes in the circuit board also must be formed as either rectangles or squares making the fabrication process somewhat difficult.
Another pertinent prior art reference is U.S. Pat. No. 3,273,134, entitled "Printed Circuit Assemblies of Magnetic Cores" by H. P. Lemaire et al. There is disclosed in the patent a circuit board onto which; circuit conductors are deposited, rectangular holes are formed through the board, and magnetic core assemblies which are washer-shaped are positioned in an endwise fashion within the rectangular holes. Again, the distinctive fabrication limitation is that rectangular holes have to be formed in the circuit board. Due to the fact that the magnetic cores do not have a polarity alignment problem, there is an ease in fabricating the assembly in that the only alignment necessary is the alignment of the magnetic core with respect to the rectangular opening. Another prior art device particularly adaptable for use with printed circuit boards is disclosed in U.S. Pat. No. 3,417,294 entitled "Mounting Circuit Elements in Printed Circuit Boards" by M. Steidlitz. In that patent there is disclosed an electronic component which is cylindrical in shape and which has a segment of the cylinder wall forming at least one electrical contact. Also provided is a tab projecting from the cylinder wall, through an area not covered by the electrical contact. The tab and contact each provide at least one electrical contact to the component. Another device of interest is disclosed in Great Britain Pat. No. 1,249,108 by R. W. Beattie entitled "Electric Circuit Assemblies". In that patent there is disclosed a cylindrical electrical component having rings affixed to either end which rings are conductive in nature and which correspond in position to the electrical contacts or conductors that are fixed to the circuit board. The opening through the circuit board is cylindrical in nature and the component is designed to be inserted in the board without angular indexing.
In order to minimize the cost and to increase the effectiveness of the automatic machinery used to insert the electronic components, it appears highly desirable that the circuit boards contain easily formed apertures, namely, holes rather than rectangular and/or odd shaped apertures, particularly apertures that require key indexing which in turn requires accurate punching and/or milling of the board. In addition, another desirable feature would be that of having the components adaptable for use in multi-layer boards, that is, where conductors which are embedded within the board at different depths can also be easily attached to the contacts of the electrical component. Another desirable feature for any automatic mounted component is to enable the component to be flow soldered into electrical contact with the conductors on the board. And to be able to remove the component from the board for circuit repair without having to destroy the board. It would also be desirable to provide an electrical component having no leads so as to minimize associated inductance.
The present invention is directed to a device which solves some of the above problems and in addition retains the advantages associated with automatic machine handling.